The late Pat Tillman continues to be loved by many for giving his life for his country after giving up his NFL career with the Arizona Cardinals. No one loved him more, however, than his widow, Marie, and she has built up the courage to share the story of their love affair.

Marie Tillman has gathered the many letters her husband wrote her during their 11-year-relationship in a new book called The Letter: My Journey Through Love, Loss, & Life. From Marie and Pat's teenage dating years together all the way through the couple's correspondence during Pat's last tour of duty as a United States Army Ranger in Afghanistan, "The Letter" chronicles their moving story.

Just before the 27-year-old Pat Tillman was killed in a friendly-fire incident eight years ago, Marie Tilllman received his final letter to her—sent "just in case" he didn't return from his latest assignment.

"Through the years I've asked a great deal of you, therefore it should surprise you little that I have another favor to ask," Pat wrote to Marie in that letter, per the New York Post. "I ask that you live."

According to the Post, Marie, now 35, has since remarried and is currently living in Chicago. Earlier this year, she also gave birth to her first son. She still, however, keeps who Pat was and what Pat said close to her heart.

"The spirit of the letter is something I still think about all the time," Marie told the Post. "I constantly ask myself, am I living life to the fullest? Am I doing all the things I should and could be doing?

Based on an extended excerpt from the book, Pat Tillman expressed how difficult it was to find something to write to Marie at the end.

"It's difficult to summarize 10 years together, my love for you, my hopes for your future, and pretend to be dead all at the same time." Pat wrote. "I simply cannot put all this into words. I'm not ready, willing or able."

Now that Marie has shared much of Pat's loving words, they are bound to touch the hearts of many more.